03. Immunogenicity and Safety of a Quadrivalent Meningococcal Conjugate Vaccine (MenACYW-TT) Administered as a Booster Dose in Adults and Adolescents Vaccinated Against Meningococcal Disease 3 - 6 Years Earlier

BACKGROUND: Booster doses of meningococcal conjugate vaccines may induce long-term protection against invasive meningococcal disease. MenACYW-TT [MenQuadfi®] is a quadrivalent meningococcal conjugate vaccine, licensed for use in ages 2 years and older in USA. The vaccine is also licensed in ages 12 months and older in EU and other countries. METHODS: A phase IIIb study (NCT04084769) was conducted to evaluate the persistence of immune response in adults and adolescents primed 3-6 years earlier with either MenACYW-TT or MCV4-CRM (Menveo®) and, safety and immunogenicity of MenACYW-TT when administered as a booster dose with or without concomitant administration with MenB vaccines (Bexsero® and Trumenba®). Serum bactericidal assays with human complement (hSBA) and baby rabbit complement (rSBA) were used to measure antibodies against vaccine serogroups at baseline (Day 0 [D0]), D06 (in a subset) and 30 days post-vaccination (D30). Safety data were collected up to 6 months post-vaccination. RESULTS: At D0, the GMTs were higher in subjects primed with MenACYW-TT vs MCV4-CRM for serogroups C, Y and W, and were comparable for serogroup A. At D0, all hSBA GMTs were higher than those observed pre-priming dose, suggesting persistence of immunity. Sufficiency of hSBA seroresponse ( >75%) was demonstrated following administration of MenACYW-TT booster dose regardless of the priming vaccine administered 3-6 years earlier. Vaccine seroresponse in a subset of participants at D06 ranged from 77.8% (95%CI 62.9%; 88.8%) for serogroup A to 97.8% (88.5%; 99.9%) for serogroup W suggesting a quick onset of immune response post-booster. Post-vaccination (D30) hSBA GMTs were comparable for serogroups A, Y and W regardless of the nature of the priming vaccine and were higher for serogroup C in subjects primed with MenACYW-TT vaccine. The MenACYW-TT booster dose was well-tolerated and had similar safety profiles regardless of the priming vaccine. The safety profiles were comparable regardless of the MenB vaccine co-administered with MenACYW-TT vaccine. CONCLUSION: MenACYW-TT used as priming vaccine was able to demonstrate persistence of immune response 3-6 years later. MenACYW-TT elicits robust booster responses in adults and adolescents primed with MenACYW-TT or MCV4-CRM DISCLOSURES: Betzana Zambrano, MD, Sanofi Pasteur (Employee) Germán Áñez, MD, Sanofi Pasteur (Other Financial or Material Support, Former employee) Sue Jiayuan, MSc, Sanofi Pasteur (Independent Contractor) Judy Pan, PhD, Sanofi Pasteur (Employee) Habiba Arroum, MD, Sanofi Pasteur (Employee) Kucku Varghese, PhD, Sanofi Pasteur (Employee) Emilia Jordanov, MD, Sanofi Pasteur (Employee, Shareholder) Mandeep S. Dhingra, MD, Sanofi Pasteur (Employee, Shareholder

Varicella epidemiology in Latin America and the Caribbean

Introduction: The Latin American Society of Pediatric Infectious Diseases (SLIPE), with the support of the Americas Health Foundation (AHF), has developed a position paper on varicella prevention in Latin America and Caribbean countries (LAC). This article summarizes the most relevant aspects of varicella in LAC, and emphasizes the need to include the varicella vaccine in the national immunization programs in the Region and evaluate its impact disease burden. Areas covered: A systematic review was conducted of the medical evidence published and presented at various regional medical conferences on the disease burden in LAC, the advances made by prevention programs, the available vaccines in the Region, and their immunogenicity, efficacy, effectiveness, and safety. The different national varicella-prevention vaccination programs were reviewed, as was available information regarding the impact of these programs on the epidemiology of varicella in those countries implementing a varicella vaccine strategy. Following that initial publication, an update was conducted, including data from additional countries in the Region. Expert commentary: Varicella is a vaccine-preventable infectious disease, considered a ‘benign disease’ because of lower complication rates when compared with measles, pertussis. The incorporation of a two-dose varicella vaccine in national immunization schedules in all countries throughout LAC would be of great benefit to the health of the children

Enhanced Surveillance for Fatal Dengue-Like Acute Febrile Illness in Puerto Rico, 2010-2012

BackgroundDengue is a leading cause of morbidity throughout the tropics; however, accurate population-based estimates of mortality rates are not available.Methods/principal findingsWe established the Enhanced Fatal Acute Febrile Illness Surveillance System (EFASS) to estimate dengue mortality rates in Puerto Rico. Healthcare professionals submitted serum and tissue specimens from patients who died from a dengue-like acute febrile illness, and death certificates were reviewed to identify additional cases. Specimens were tested for markers of dengue virus (DENV) infection by molecular, immunologic, and immunohistochemical methods, and were also tested for West Nile virus, Leptospira spp., and other pathogens based on histopathologic findings. Medical records were reviewed and clinical data abstracted. A total of 311 deaths were identified, of which 58 (19%) were DENV laboratory-positive. Dengue mortality rates were 1.05 per 100,000 population in 2010, 0.16 in 2011 and 0.36 in 2012. Dengue mortality was highest among adults 19-64 years and seniors ≥65 years (1.17 and 1.66 deaths per 100,000, respectively). Other pathogens identified included 34 Leptospira spp. cases and one case of Burkholderia pseudomallei and Neisseria meningitidis.Conclusions/significanceEFASS showed that dengue mortality rates among adults were higher than reported for influenza, and identified a leptospirosis outbreak and index cases of melioidosis and meningitis

Measuring the water and soil environments

<p>Characteristics of all fatal laboratory-positive dengue case-patients detected by the Enhanced Fatal AFI Surveillance System, Puerto Rico, 2010–2012.</p

Enhanced Surveillance for Fatal Dengue-Like Acute Febrile Illness in Puerto Rico, 2010-2012

<div><p>Background</p><p>Dengue is a leading cause of morbidity throughout the tropics; however, accurate population-based estimates of mortality rates are not available.</p><p>Methods/Principal Findings</p><p>We established the Enhanced Fatal Acute Febrile Illness Surveillance System (EFASS) to estimate dengue mortality rates in Puerto Rico. Healthcare professionals submitted serum and tissue specimens from patients who died from a dengue-like acute febrile illness, and death certificates were reviewed to identify additional cases. Specimens were tested for markers of dengue virus (DENV) infection by molecular, immunologic, and immunohistochemical methods, and were also tested for West Nile virus, <i>Leptospira spp</i>., and other pathogens based on histopathologic findings. Medical records were reviewed and clinical data abstracted. A total of 311 deaths were identified, of which 58 (19%) were DENV laboratory-positive. Dengue mortality rates were 1.05 per 100,000 population in 2010, 0.16 in 2011 and 0.36 in 2012. Dengue mortality was highest among adults 19–64 years and seniors ≥65 years (1.17 and 1.66 deaths per 100,000, respectively). Other pathogens identified included 34 <i>Leptospira spp</i>. cases and one case of <i>Burkholderia pseudomallei</i> and <i>Neisseria meningitidis</i>.</p><p>Conclusions/Significance</p><p>EFASS showed that dengue mortality rates among adults were higher than reported for influenza, and identified a leptospirosis outbreak and index cases of melioidosis and meningitis.</p></div

Incidence of laboratory-positive dengue, and observed and expected number of fatal laboratory-positive dengue cases by municipality of residence and year, Puerto Rico, 2010–2012.

<p>Left panels: Incidence per 100,000 population of non-fatal, laboratory-positive dengue cases reported to the Passive Dengue Surveillance System, and number of fatal laboratory-positive dengue cases identified by the Enhanced Fatal AFI Surveillance System. Right panels: the standard deviation (SD) of the standard residuals are displayed. Differences >2 SD denotes significantly fewer than expected fatal laboratory-positive dengue cases, while ≤2 SD denotes significantly more than expected fatal laboratory-positive dengue cases.</p

Diagnostic laboratory results for fatal laboratory-positive dengue cases detected by the Enhanced Fatal Acute Febrile Illness Surveillance System, Puerto Rico 2010–2012.

<p>Diagnostic laboratory results for fatal laboratory-positive dengue cases detected by the Enhanced Fatal Acute Febrile Illness Surveillance System, Puerto Rico 2010–2012.</p

Clinical features and outcomes for fatal laboratory-positive dengue case-patients detected by the Enhanced Fatal AFI Surveillance System, Puerto Rico, 2010–2012.

<p>Clinical features and outcomes for fatal laboratory-positive dengue case-patients detected by the Enhanced Fatal AFI Surveillance System, Puerto Rico, 2010–2012.</p